diff options
Diffstat (limited to 'kernel/include/linux/poll.h')
| -rw-r--r-- | kernel/include/linux/poll.h | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/kernel/include/linux/poll.h b/kernel/include/linux/poll.h new file mode 100644 index 000000000..c08386fb3 --- /dev/null +++ b/kernel/include/linux/poll.h @@ -0,0 +1,164 @@ +#ifndef _LINUX_POLL_H +#define _LINUX_POLL_H + + +#include <linux/compiler.h> +#include <linux/ktime.h> +#include <linux/wait.h> +#include <linux/string.h> +#include <linux/fs.h> +#include <linux/sysctl.h> +#include <asm/uaccess.h> +#include <uapi/linux/poll.h> + +extern struct ctl_table epoll_table[]; /* for sysctl */ +/* ~832 bytes of stack space used max in sys_select/sys_poll before allocating + additional memory. */ +#define MAX_STACK_ALLOC 832 +#define FRONTEND_STACK_ALLOC 256 +#define SELECT_STACK_ALLOC FRONTEND_STACK_ALLOC +#define POLL_STACK_ALLOC FRONTEND_STACK_ALLOC +#define WQUEUES_STACK_ALLOC (MAX_STACK_ALLOC - FRONTEND_STACK_ALLOC) +#define N_INLINE_POLL_ENTRIES (WQUEUES_STACK_ALLOC / sizeof(struct poll_table_entry)) + +#define DEFAULT_POLLMASK (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM) + +struct poll_table_struct; + +/* + * structures and helpers for f_op->poll implementations + */ +typedef void (*poll_queue_proc)(struct file *, wait_queue_head_t *, struct poll_table_struct *); + +/* + * Do not touch the structure directly, use the access functions + * poll_does_not_wait() and poll_requested_events() instead. + */ +typedef struct poll_table_struct { + poll_queue_proc _qproc; + unsigned long _key; +} poll_table; + +static inline void poll_wait(struct file * filp, wait_queue_head_t * wait_address, poll_table *p) +{ + if (p && p->_qproc && wait_address) + p->_qproc(filp, wait_address, p); +} + +/* + * Return true if it is guaranteed that poll will not wait. This is the case + * if the poll() of another file descriptor in the set got an event, so there + * is no need for waiting. + */ +static inline bool poll_does_not_wait(const poll_table *p) +{ + return p == NULL || p->_qproc == NULL; +} + +/* + * Return the set of events that the application wants to poll for. + * This is useful for drivers that need to know whether a DMA transfer has + * to be started implicitly on poll(). You typically only want to do that + * if the application is actually polling for POLLIN and/or POLLOUT. + */ +static inline unsigned long poll_requested_events(const poll_table *p) +{ + return p ? p->_key : ~0UL; +} + +static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc) +{ + pt->_qproc = qproc; + pt->_key = ~0UL; /* all events enabled */ +} + +struct poll_table_entry { + struct file *filp; + unsigned long key; + wait_queue_t wait; + wait_queue_head_t *wait_address; +}; + +/* + * Structures and helpers for select/poll syscall + */ +struct poll_wqueues { + poll_table pt; + struct poll_table_page *table; + struct task_struct *polling_task; + int triggered; + int error; + int inline_index; + struct poll_table_entry inline_entries[N_INLINE_POLL_ENTRIES]; +}; + +extern void poll_initwait(struct poll_wqueues *pwq); +extern void poll_freewait(struct poll_wqueues *pwq); +extern int poll_schedule_timeout(struct poll_wqueues *pwq, int state, + ktime_t *expires, unsigned long slack); +extern long select_estimate_accuracy(struct timespec *tv); + + +static inline int poll_schedule(struct poll_wqueues *pwq, int state) +{ + return poll_schedule_timeout(pwq, state, NULL, 0); +} + +/* + * Scalable version of the fd_set. + */ + +typedef struct { + unsigned long *in, *out, *ex; + unsigned long *res_in, *res_out, *res_ex; +} fd_set_bits; + +/* + * How many longwords for "nr" bits? + */ +#define FDS_BITPERLONG (8*sizeof(long)) +#define FDS_LONGS(nr) (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG) +#define FDS_BYTES(nr) (FDS_LONGS(nr)*sizeof(long)) + +/* + * We do a VERIFY_WRITE here even though we are only reading this time: + * we'll write to it eventually.. + * + * Use "unsigned long" accesses to let user-mode fd_set's be long-aligned. + */ +static inline +int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset) +{ + nr = FDS_BYTES(nr); + if (ufdset) + return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0; + + memset(fdset, 0, nr); + return 0; +} + +static inline unsigned long __must_check +set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset) +{ + if (ufdset) + return __copy_to_user(ufdset, fdset, FDS_BYTES(nr)); + return 0; +} + +static inline +void zero_fd_set(unsigned long nr, unsigned long *fdset) +{ + memset(fdset, 0, FDS_BYTES(nr)); +} + +#define MAX_INT64_SECONDS (((s64)(~((u64)0)>>1)/HZ)-1) + +extern int do_select(int n, fd_set_bits *fds, struct timespec *end_time); +extern int do_sys_poll(struct pollfd __user * ufds, unsigned int nfds, + struct timespec *end_time); +extern int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp, + fd_set __user *exp, struct timespec *end_time); + +extern int poll_select_set_timeout(struct timespec *to, long sec, long nsec); + +#endif /* _LINUX_POLL_H */ |